Hi! I'm not sure I'll join the jam yet, but in order to make a decision, I'd like to know, well, what the title says. Does this speculative evolution have to be set in a fairly realistic sci-fi setting (either an alien planet or an alternate or future Earth), or can it be set in a more magical world? One where the environmental conditions are influenced by the presence of magic or other supernatural forces, and life had to adapt to it in ways that are impossible under normal laws of physics?

Technically - they are defined as "biology of If the.."' The definition can be bent a bit. In bending it, even if it is defined as science-realistic, there are quite a few projects that have dealt with the subject that magic was a component in the evolution of animals.

So you can deal with this issue in this direction. The only condition is that the magic has some kind of limitation, like a physical law.

In short - yes, you can mess with evolution around magic as long as it has clear rules and limitations.

Feel free to look here at the question regarding it.